Electronics > Beginners
How do I make an LED light up using a comparator?
alsetalokin4017:
--- Quote from: renzoms on October 22, 2019, 12:38:11 am ---5V rail > resistor > LED cathode - anode > Pin 1
--- End quote ---
Shouldn't the anode be on the + 5v side?
renzoms:
You are correct. I mixed up the names
renzoms:
Got it to work although the timing is not accurate. Not looking into it rn.
If my + voltage is higher than my reference voltage at - then output at Pin 1 should be High, so for this n channel open drain output, that means ?????
When the reference voltage, -, is higher than the voltage at the + terminal, the output at Pin 1 should be Low, so for this n channel open drain that means???
renzoms:
The timing is about over 4 seconds but it is calculated at 3.7s....
Audioguru again:
--- Quote from: renzoms on October 22, 2019, 12:38:11 am ---5V rail > resistor > LED cathode - anode > Pin 1
--- End quote ---
No, you have the polarity of the LED connected backwards. The LED anode must have its current-limiting resistor connected to +5V and the LED cathode gets pulled to ground by the comparator output pin 1.
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